Philosophy of Being and Knowledge

Logic (Philosophy of Thought)

Definition, Terminology, History

Logic is a philosophical discipline that studies the forms and laws of correct thinking. It is natural for humans to think, and the process of thinking accompanies us constantly. How does thinking occur? - this is the question that logic seeks to answer. The term "logic" derives from the Greek word "λόγος" (logos), meaning "thought," "reason," or "word." This term originated in Ancient Greece. The ancient Greek philosopher Heraclitus was the first to use "logos" as a philosophical term, asserting that a rational principle underlies everything that exists, governing the coming into being, passing away, and transformation of all things. Heraclitus referred to this principle as "logos." Since "logos" in Heraclitus' philosophy represents the rational principle of the world, it came to signify the collection of rational laws and, eventually, the science of the forms and laws of correct thinking.

Before addressing when logic emerged, it is essential to distinguish between its two aspects: 1) logic as principles of thought and 2) logic as the science of thought.

• Logic as Principles of Thought is eternal. Since the advent of humanity, humans have been thinking, thus employing logical laws. Therefore, as long as humans have existed, they have actively used logic. Even if humans did not exist, the laws of logic would still be true. For instance, the law of identity, commonly expressed as "A=A," is true regardless of human existence.
• Logic as a Science that studies the laws and forms of correct thinking emerged in the ancient cultures of India and Greece. In European tradition, the foundations of logic laid in Ancient Greece were developed further.

The greatest contribution to the development of logic was made by the ancient Greek philosopher Aristotle (384-322 BCE), who authored a series of works dedicated to logic. Aristotle's collection of works on logic is known as the "Organon." After Aristotle, his ideas were further developed by other schools and philosophical movements, but throughout Antiquity and the Middle Ages, logicians adhered to Aristotle's achievements, merely interpreting and elucidating his ideas.

Significant advancement in logic occurred at the end of the 19th and beginning of the 20th century. Contemporary logic is characterized by two main directions:

• Classical Logic refers to logic in which the principle of bivalence is maintained, meaning that every proposition is either "true" or "false," with no other truth values. This principle is known as the principle of bivalence. Classical logic continues the legacy of Antiquity and the Middle Ages.
• Non-Classical Logic refers to systems that reject the principle of bivalence, asserting that more than two truth values are possible. This type of logic is also known as multi-valued logic.